The present disclosure relates to a magnetic sheet for a wireless power charging system.
In parallel with the reduction in the weights of electronic devices due to miniaturization, non-contact power charging methods for charging a battery using magnetic coupling without electrical contact have been developed. Such non-contact power charging methods include wireless power charging methods.
The wireless power charging method, which is a method of charging a battery using electromagnetic induction, charges a battery by converting into energy the power generated by inductive coupling between a primary coil (e.g., a transmitter coil provided in a charger such as a wireless power transmission device) and a secondary coil (e.g., a receiver coil provided in an object to be charged, such as a wireless power reception device).
For wireless power charging purposes, a magnetic sheet may be disposed between the receiver coil and the battery. The magnetic sheet may increase the efficiency of transmission of electromagnetic waves generated from the wireless power transmission device to the wireless power reception device, and may thereby increase power charging efficiency.
Meanwhile, since the receiver coil is formed of copper (Cu) having low resistance in order to improve magnetic induction therein, the magnetic sheet should have high magnetic saturation Ms and permeability μ′ values, and low core loss and magnetic force loss, in order to significantly increase power charging efficiency.